Okay, make sure you have all of the following .dll files in the SAME folder as Maped3.exe:
corona.dll
MRU.dll
pr2-common-cpp.dll
RegisterFileType.dll
Render.dll
zlib.net.dll
Only other thing I can think of causing it, is maybe there's some odd discrepancy between dlls in XP and Vista (but there shouldn't be), or one of the dlls itself is throwing an exception.
EDIT: Not having Render.dll definitely nukes the thing right away with this error:
EDIT 2: It occurred to me, maybe it's crashing when it can't find MapedPreferences.xml, which seems silly. Try making sure you have a pre-existing one and copy it into your maped folder.